Refrigerating apparatus



June 22; 1943. A. BEALS 2,322,339

REFRIGERATING APPARATUS Filed Feb. 26, 1938 '7 Sheets-Sheet 1 IN-VENTOR.

ATTORNEYS.

June 22, 1943. BEALs 2,322,339

REFRIGERATING APPARATUS Filed Feb. 26, 1938 7 Sheets-She et 2 INVENT OR.

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ATTORNEYS- June 22, 1943. A. E. BEALS REFRIQERATING APPARATUS Filed Feb. 26. 1938 '7 Sheets-Sheet 3 a INVENTOR. wmfia ATTORNEY5 June 22,1943. A. E. BEALS 3,322,339

RE FRIGERATING APP ARATUS Filed Feb. 26, 1938 7 Sheets-Sheet 4 INVENT OR.

44332 8. M i gw wwzw ATTORNEYS.

June 22, 1943.

A; BEA LS 2,322,339

REFRIGERATING APPARATUS Filed Feb. 26, 1938 '7 Sheets-Sheet 5 INVENTOR.

3 BY WM9$ ATTORNEYb.

June 22, 1943. BEALS 2,322,339

REFRIGEBATING APPARATUS Filed Feb. 26, 1958 7 Sheets-Sheet 6 7 INVENTOR.

W Mwrviw ATTORNEY.

REFRI GERAT I NG APPARATUS Filed Feb. 26, 1938 7 Sheets-Sheet 7 INVENTOR.

ATTORNEY.

Patented June 22, 1943 UNlTED STATES PATENT OFFICE REFRIGERATING APPARATUS Albert E. Beals, Norwich, N. Y. A ppiication February 26, 1938, Serial No. 192,849

3 Claims.

This invention relates to an apparatus for controlling the operation of air conditioning equipment.

The term air conditioning equipment, as here used, is to be interpreted as a broad and most inclusive term. It is not to be confused with the general understanding of the term air conditioning apparatus.

Air conditioning equipment, designed for cooling and dehumidifying, or humidiiying as occasion demands, is purely refrigerating equipment in its entirety. The air conditioning apparatus, generally considered to be preeminent, is merely a small part of the total equipment.

Considered as a unit, air conditioning equipment consists of, primarily, a vapor compressor with its motive power; second, a heat absorbing unit into which the heat extracted from the air to be cooled is transferred, either directly or indirectly; and third, a condensing unit to which the absorbed heat is delivered by the compressor and from which it is extracted and carried away from the system.

The popular conception of the air conditioning apparatus merely consists of an enlargement in the duct system through which the air to be cooled is circulated. In this enlarged portion of the duct system is placed either the heat absorbing unit itself, for direct absorption of heat, or water, in the form of spray which has been cooled by the heat absorbing unit, for indirect transfer of heat.

An object of this invention is to provide a control by means of which the relative humidities of an enclosure to be conditioned have definite and predetermined relations to the temperatures therein, said temperatures varying from time to time as may be required.

Another object is to provide a control whereby the capacity of the vapor compressor for carrying heat from the heat absorbing unit to the condensing unit may be automatically varied in accordance with varying requirements of the refrig crating load in the enclosure.

Still another object is to provide a control whereby the temperature and corresponding relative humidity within an enclosure may be changed to another temperature and relative humidity by either manual manipulation or automatically, through remote control means from some distant station, the changed relative humidity bearing a predetermined relation to the changed temperature.

Another i to provide means whereby a multiplicity of conditioning units, individually equipped with this control, may be regulated synchronously from a remote station so that the enclosures served by the several units may each be maintained at the same variable temperatures and relative humidities.

And another object is to provide a thermostat and a hygrostat having registering members which are free to move through desired ranges of temperatures and relative humidities, the range of relative humidities bearing a definite and predetermined relation to the range of temperatures.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred form of the present invention is clearly shown.

In the drawings:

Fig. 1 is an elevational view showing the front side of my novel control instrument;

Fig. 2 is a rear elevational view of my control instrument;

Fig. 3 is a side elevational view of my control instrument with parts broken away so as to more clearly show certain details of construction;

Fig. 4 is a fragmentary, elevational view showing the arrangement of the contacts;

Fig. 5 is a sectional view taken on line 55 of Fig. 4;

Fig. 6 is a diagrammatic view illustrating the manner in which my novel control apparatus may be employed in connection with air conditioning apparatus; and

Fig. '7 is a circuit diagram illustrating the oper ation of the control system.

For obtaining a desired degree of comfort for people assembled in rooms, auditoriums, schools, or the like, it has been found necessary, especially during the summer months, to not only regulate the dry-bulb temperatures of the air in such enclosures within certain limits but also to regulate the relative humidities in definite relations to the temperatures.

Fig. 8 shows the preferred scope of travel for the registering members of the thermostat and the hygrostat and also a preferred relationship between the temperature and the relative humidity scales;

Fig. 9 is a view corresponding to Fig. 1 showing a modified arrangement;

Fig. 10 is a side, elevational view of the modifled arrangement with parts broken away so as to more clearly show certain details of construction; and

Fig. .11 is a diagrammatic showing of the circuit for energizing the solenoids.

The control instrument, as illustrated in the drawings, consists of a supporting plate which carries a temperature responsive member 12 on its one face and a humidity responsive element l4 on its other face. The temperature responsive instrument comprises a spiral bimetallic member l5, one end of which is secured to the mounting stud i8 carried by the base H1. On the outer end of the temperature responsive element IE is carried a block of insulation which in turn carries a plurality of contact mem bers 22, 23, 24, and 25. These contact members cooperate with a plurality of contact members 28, 29, 30, 3|, 32, 33, 34, and carried by an insulating support 35 which is pivotally mounted on the supporting stud IS. The contact support 36 has a depending member 38 secured thereto which is provided with gear teeth 40 which mesh with gear teeth on pinion 42 of the member 44 carried by the member 46. The member 44 is also provided with a set of gear teeth which mesh with the teeth on the rack 52.

This rack 52 may be made responsive to outside effective temperatures so as to cause the instrument to be adjusted to maintain higher indoor effective temperatures at higher outdoor effective temperatures. The effective temperature instrument responsive to outdoor conditions which is used for operating the rack 52 is similar to that shown in my Patent No. 1,986,316; the rack or slide 52 corresponding to the slide 14 of the patent; the slide 54 corresponding to the slide l2 of the patent; and the slide 56, likewise, corresponding to the slide l3 of the patent. The means for operating the slides 54 and 5B is the same as the means used in operating the slides l2 and I3 of the device shown in my patent. For a complete description of the outside effective temperature responsive means reference may be had to my above mentioned patent. While I have disclosed an outside effective temperature responsive means similar to the outside effective temperature responsive means disclosed in the above mentioned patent, it is obvious that other types of outside effective temperature responsive means may be substituted for the particular means shown.

The arrangement is such that a change in the outside eifective temperature Will shift the stationary contacts carried by member 36 to such an extent that the conditioning equipment will maintain the inside effective temperature in predetermined relation to the effective temperature outside.

A cam member is pivotally mounted on the insulating support 36 and is provided with an operating handle 62. The purpose of the cam 60 is to make it possible for one to manually move the outer end of the temperature responsive member l2 to the extreme left, thereby shutting down the air conditioning equipment in a manner to be explained hereinafter. A plurality of stop pins 64 and 66 limit the movement of the cam 60. When the cam 60 is in the position shown in Fig. 1, the contact carrying block 20 is permitted to move to the extreme right; whereas, when the cam 60 is rotated so as to engage with the stop 66, the contact block 20 is held in the extreme left position.

Also carried by the member 36 are a pair of contacts 68 and 10 which cooperate with a contact 12 carried by the arm 14. The arm '14 is pivotally mounted on the reverse side of the supporting plate I0 by means of a pivot '16. The

arm H is adapted to be actuated in response to changes in humidity within the room, A U- shaped block is carried by the base plate H), in one arm of which there is slidably supported a member 532 which may be adjusted vertically by means of an adjusting screw 84 carried by the other arm of the U. The slide member 82 is slotted as shown and serves to freely support one end of the lever 88. The slot in the slide member 62 serves to restrict the lateral motion of the lever 88 but said lever is free to move vertically away from the supporting surface at the bottom of the slot.

The pivot pin 86 connects this end of the lever 83 with the end of the section 90 oithe humidity responsive material.

The end of the lever 83 being freely supported in the slotted member 82 and free to move vertically assures that a strain cannot be induced in the sections til-9| greater than that normally exerted by the tension in the spring 98.

As best shown in Fig. 2, the humidity responsive material is in two sections 90 and SI each of which is made up of a plurality of separate strands of material which, for example, may be human hairs. The efifect which changes in humidity has on material of this kind is Well known and need not be described. Adjacent the upper end of the base plate [5 there is provided a pivot member 92 which pivotally supports a lever 94. This lever serves to support the two sections of the hygroscopic material as shown in Fig, 2. A spring member 93 is provided for tensioning the hygroscopic element.

A bell crank I64 is pivotally mounted on a pin H12 which is carried by the base l0. One arm of the bell crank is actuated in one direction by the contraction of the humidity responsive material 99-91. When the outer end of the lever 88 is in contact support with the member 82, the tension in the spring 88, acting through the lever 88, moves the bell crank H14 in the opposite direction upon an expansive movement of the humidity responsive material 9il-9l. The other arm of the bell crank is provided with a gear sector hi6 which meshes with the gear sector I08 carried by the contact supporting arm i i. From this arrangement, it will be seen that a change in humidity will cause the contact arm 14 to move either to the right or to the left depending on the humidity change. As shown in Fig. 2, very slight movement of the contact 12 is necessary to close the circuit. In this way the relative humidity in the room m? be very closely controlled.

The outside effective temperature responsive mecl'ianism may also be supported from the rear of the supporting plate It. The outside effective temperature mechanism has been designated by the reference numeral l i l; and the Wet and dry bulbs, which are adapted to be placed outside of the enclosure, have been designated by the reference numerals H2 and il respectively. The wet nd dry bulbs iii. and EM correspond to the ouibs 92 and 93 respectively of my afore mentioned patent.

In 6 I have shown diagrammatically a room H5 in which is placed one of my control instruments. The apparatus for conditioning the air for til room includes a ioui cylinder compressor ii'i which is driven by a motor H6. The compressor ii! is adapted to compress refrigerant and discharge the compressed refrigerant through the pipe H8 into the condenser H!) from whence th liquid refrigerant may flow through the line I26 into the evaporator I22. The usual form of restrictor valve I24 is provided for controlling the flow of refrigerant through the evaporator. The evaporated refrigerant returns to th compressor through the return line I26. The condenser is a water cooled condenser which is provided with the usual form of water coil I28. The amount of water flowing through the coil I28 is determined by the valve I39.

The evaporator I22 is mounted within the chamber 'l3I which chamber is connected at the one end by a suitable conduit I34 with the enclosure 1 I5 and by another conduit ISilwith the outside atmosphere. A fan I32 driven by motor I33 circulates air through the chamber and discharges the conditioned air through the condu t I38 into the enclosure H5, A damper I39 is provided for controlling the flow of air through the conduits I34 and 538. This damper may be manually controlled and, coincidentally therewith, it may be automatically controlled to entirely close the conduit I34. from the enclosure II5 whenever the outside vet-bulb temperature drops below the desired wet-bulb temperature within the enclosure.

In order to control the humidity conditions within the room, a by-pass Mil has been provided through which at least a portion of the air being circulated may pass thereby avoiding the evaporator i122. The icy-pass we is provided with a control damper I42 operated a solenoid Hi l which is under the control of the humidostat hereinbeiore described. The thermostat controls the operation of the compressor in a manner to be described hereinafter. The compressor is a four-cylinder unit which is provided with solenoid valves i 38, 52, and I53 in the suction lines leading to three of the cylinders. Closing all the solenoid valves has the effect of unloading the three cylinders of the compressor, While I have shown this arrangement for unloading the compressor, it is to be understood that any of the usual unloading eirpedients may be used, such as opening a by-pass, opening th discharge valves, etc.

Referring now to Fig. '7 in which I have shown the circuit arrangement .used, it will be observed that there are five remote control switches I54, I55, 56, 51, and i5l3,.'the first of which controls the compressor and fan motors, three of which control the unloading valves and the last of which controls the by-pass damper l t-2. The remote control switch W4 .is connected directly into the main supply lines and controls the operation of the compressor motor IIG and the blower motor I33.

The control switches 154 through 558 ar the standard form of remote control switches which are commonly used and which operate as follows: The solenoid Ito, when energized, automatically closes the multiple switch H52 and holds this switch clcsedso long as the solenoid is energized. In order to open the multiple circuit switch IE2, a short circuit is placed around the solenoid Hi0 thereby deenergizing the solenoid. Referring .now to the switch 155 which is similar to the switches ltd through l58, except that .it is a three-wire switch whereas the others are twowire switches; it will be seen that, when the movable contact 22 engages the stationary contact 29, .a circuit is completed from th line C through the contacts 29-42, through the solenoid I66 and the resistance EM to the main line A. This energizes the solenoid IE!) thereby closing the multiple switch 152. Closingoftheswitch Hi2 closes a stick circuit from the main line C through the solenoid Ills, through the resistance I6 to the main line A, with the result that the contact 22 may leave the contact 29 without deenergizing the solenoid.

In order to open the main remote control switch 554, a short circuit is placed across the solenoid I56. This takes place when the contact 22 en gages the contact 28. When the contact 22 is in engagement with the contact '25, no current flows through the solenoid I69 since all of the current will flow through the shunt circuit which includes conductor Itl, contacts 28-22, and the conductor I5Ia.

It will be further noted that each of the contact rings 22 through 25 controls aseparate one of the remote control switches hereinabovc described. The contact ring 22, for example, closes the cirthrough the remote control switch J54 when it engages with the stationary contact 28 and opens the circuit through the same remote control switch when it engages the contact 28. In similar manner, contact 23 cooperates with stationary contacts 30 and ill to open and close the circuit through the control switch I55; contact 2- cooperates with the stationary contacts to open and close the circuit through the remote control switch 855; and, contact 2-5 on :eraies with the contacts and to open and close the circuit through the remote control switch i'al.

As the contact carrying member 25 moves from the extreme left to the right, the circuits through the remote control switches I 56 through I51 are consecutively closed; and, as the contact carrier 20 moves from the extreme right to the left, the circuits are opened through these control switches in the reverse order. Obviously, the contact carrying member will not always move from one extreme to the other but may move any portion of the distance.

The remote control switch I58 is under control of the humidity responsive mechanism; and, referring again to Fig. '7, it will be noted that, when the humidity is high the movable contact I2 will engage the stationary contact E3, closing a circuit through the solenoid 5% of the remote control switch I58 with the result that the solenoid I44 will close the butterfly damper 52. Upon the humidity being lowered the desired amount the contact I2 will swing into engagement with the contact it with the result that the damper I42 will be opened.

Considering now that the temperature within the room is increasing and that the contact carrying member 20 moves from the extreme left to the right, the following will take place: The movable contact 22 will, first, engage the contact '29 with the result that the compressor mechanism will start up as just explained. Only the first cylinder will do any pumping, however, as the solenoid valves I53, I52, and I are all closed. Further movement of the contact carrying mem-- ber 20 will cause the contact member 23 to .engage the contact 3i with the result that the circuit through the remote control switch I will be closed thereby opening the solenoid operated valve I53. Further movement of the contact carrying member 20 will cause the contact 24 to engage the contact 33 with the result that the solenoid valve I52 placed in the suction line of the third cylinder of the compressor will be opened. Further movement of the contact carrying member 29 will cause the-contact 25 to engage the stationary contact '35 whereby the solenoid valve "I50 in the suction line of the fourth cylinder of the compressor will be opened.

Upon the decrease in the temperature within the room the movable contact carrying member will move from the right to the left. In so moving, the contact will first engage the contact 34 with the result that the solenoid valve I50 will be closed. A further decrease in the temperature will cause the contact member 24 to engage the stationary contact 32. This, in turn, deenergizes the solenoid of the remote control switch I56 with the result that the olenoid valve I52 is again closed. Further decrease in the temperature within the room will cause the contact 23 to engage the stationary contact which, in a similar manner, will cause the solenoid valve I53 to close. Still further decrease in the temperature within the room will cause the contact 22 to engage the stationary contact 28 with the result that the main remot control switch I54 will be opened, thereby completely closing down the air conditioning system. By virtue of such an arrangement, it is possible to vary the loading of the compressor in accordance with refrigeration requirements; and to control the amount of air passing over the evaporator, and thereby control the humidity within the room. It will be noted that when the circuit is broken through the main remote control switch I54, the current supply for the humidity control circuit is cut on.

Special attention is called to the novel manner in which the movable contacts 22 through 25 are supported. As best shown in Figs. 4 and 5, the movable block 20 carries a plurality of U-shaped contact supporting members 31 which loosely support the movable contacts in the manner shown. The movable contacts are in the form of rings which are loosely supported on the U- shaped contact supports 31. This arrangement provides for a two-point support, thereby assuring proper alignment of the contacts as they move away from the vertical center line, and preventing the contacts from swinging out of position, as they otherwise might do if they were suspended from a pin support. This arrangement also provides for a minimum amount of resistance to movement, with the result as the temperature increases or decreases, the movable contact rings 22 through 25 may pass over the stationary contacts without offering any appreciable resistance to movement.

In Figs. 9, 10, and 11, I have shown a second modification with which a different type of outside eifective temperature integrator may be used. The instrument shown in this second modification has the same contact arrangement and is intended to be used in systems of the type shown in Figs. 6 and 7. As will be pointed out hereinafter, the arrangement shown in the second modification is especially well adapted for installations where it is desirabl to permit either raising or lowering the inside conditions to suit individual preferences and in which it is desirable to synchronously regulate a number of inside controls from one master integrator located at a point remote from the individual controls.

In this second modification the member 46 carries a ratchet wheel 24! operable in reverse directions through engagement by the pawls 23924l. The pawls 239- 24l are pivotally mounted upon a lever member 243, alternatively pivotal about the pins 245-249. A channel shaped member 250 supports the pins 245249 in slotted bearings without restriction in an upward direction. At the ends of the lever 243 are pivotally hung solenoid cores 25l252 in operable relation with their respective electromagnetic coils 253-254. A roller stop member 255 is pressed upon the teeth of the ratchet 241 by means of a spring 256. Through the action of the roller 255 the motion of the ratchet is restricted to equal increments of movement and is held in positive positions.

In operation, if an electric current is passed through the solenoid coil 253, the electro-magnetic force tends to pull the core 25l into the magnetic center position, thus moving the lever 243 about the pin 245 and engaging the pawl 24! with the ratchet wheel 247. In this manner the contact support 36 is moved clockwise and the control is reset to maintain a higher temperature and a lower relative humidity within the enclosure. When the current is cut off, the solenoid coil 253 is deenergized and the lever 243 drops into the neutral position. Conversely, ii the solenoid coil 254 is energized, the contact support 36 is moved counterclockwise and the control is reset to maintain a lower temperature and higher relative humidity within the enclosure It is to be noted that when neither of the solenoid coils 253 -254 is energized, the pawls 239- 24! are entirely out of contact with the ratchet wheel 24'! and the instrument is free to be manually reset through the knob 48. The current for energizing the solenoids 253-254 may be turned on from remote switches, manually operated; from switches, automatically operated and remotely located; or the current may be controlled by means of the effective temperature slide of the control instrument disclosed in my former Patent No. 1,986,316.

If used in connection with the device disclosed in the above patent, the inside effective temperatures may then be regulated by this control in predetermined relations to the outside effective temperatures. Also a plurality of air conditioning units, individually equipped with the device herein disclosed, may be controlled synchronously from one outside effective temperature slide, located at any convenient place.

In Fig. 11 I have shown an arrangement for synchronously operating the solenoids of a plurality of separate control instruments which may be located at widely separated points. Reference numerals 260 and 26! represent the source of electric power. The solenoids for one control instrument are represented by 253a and 254a, while 253D and 254D are similar solenoids for another control instrument which it might be desirable to regulate simultaneously with the first from a remote control. A double throw switch, 262, arranged to be either manually or automatically operated and which is normally open, represents the means by which either one of the pair of solenoids on all of the control instruments connected in the circuit may be energized. When it is desired to regulate one, or any number, of controls in accordance with the outside effective temperature, the switch E would be operated automatically from an outside effective slide such as 52 shown in Fig. 1. In this manner, an office building with a number of individual units can be modified by outside conditions from one integrating instrument. At the same time, any one or more of the separate controls may be set either forward or back, according to the individual preference of the occupants, by means of the control knob 48.

While the form of embodiment of the invention as herein disclosed, constitutes a preferred form,

it is to be understood that other forms might be adopted, all coming within the scope of the claims which folloW.

What is claimed is as follows:

1. An instrument for controlling the operation of air conditioning equipment comprising, in combination, a thermostatic element responsive to variations in the temperature of air in an enclosure; a hygrostatic element responsive to variations of relative humidity of air in said enclosure, an adjustable element, common to both the thermostatic and hygrostatic elements and coacting synchronously with each; a ratchet, adapted to move in reverse directions and operatively connected with said adjustable element; two contra-positioned pawls, adapted to engage the teeth of said ratchet; a reversibly acting lever, adapted to be fulcrumed at either of two points and pivotally supporting said pawls; two electromagnets, oppositely connected with said lever and adapted to move same in reverse directions; and electric conducting means for alternatively energizing the solenoid coil of either electromagnet.

2. In combination with an enclosure to be air conditioned; air conditioning equipment comprising a compressing unit, a condensing unit and an evaporating unit in refrigerant fiow relationship; a controllin unit comprising, in combination, hygrostatic means responsive to variations of relative humidity for varying the amount of air passing over the evaporating unit; thermostatic means responsive to variations of temperature for progressively varying the capacity of said compressing unit; and an adjustable element, common to both the thermostatic and the hygrostatic elements and coacting synchronously with each.

3. Apparatus for synchronously controlling a multiplicity of air conditioning units which com prises a control instrument for each conditioning unit, each of said control instruments comprising a thermostatic element responsive to variations in temperature of air within its respective enclosure, a hygrostatic element responsive to variations of relative humidity within its respective enclosure, an adjustable element coacting with the temperature and relative humidity responsive elements to determine the responding positions of said thermostatic and hygrostatic elements, and elecetromagnetic means for varying the position of said adjustable element of each instrument, and electrical means for synchronously energizing a multiplicity of said electromagnets from a remote control station.

4. In combination with a multiplicity of units for varying the temperature and the humidity of air, first means for individually controlling said units so as to control the variation in the temperature produced by said units, second means for controlling the variation in the humidity produced by said units, means operated by said first means rendering said second means inoperative and means common to said first and second means for adjusting the operation of said first and second means.

5. In combination with an enclosure to be air conditioned; air conditioning equipment comprising a compressing unit, a condensing unit and an evaporating unit in refrigerant flow relationship; a controlling unit comprising in combination, hygrostatic means responsive to variations of relative humidity for varying the amount of air passing over the evaporating unit; thermostatic means responsive to variations of temperature for progressively varying the capacity of said compressing unit; an adjustable element, common to both the thermostatic and the hygrostatic elements and coacting synchronously with each; and means responsive to the temperature outside said enclosure for operating said adjustable element.

6. An instrument for controlling the operation of air conditioning equipment comprising, in combination, a thermostatic element responsive to variations in the temperature of air in an enclosure; a hygrostatic element responsive to variations of relative humidity of air in said enclosure, an adjustable element, common to both the thermostatic and hygrostatic elements and coacting synchronously with each; a ratchet, adapted to move in reverse directions and operatively connected with said adjustable element; two contra-positioned pawls, adapted to engage the teeth of said ratchet; a reversibly acting lever, adapted to be fulcrumed at either of two points and pivotally supporting said pawls; two electromagnets, oppositely connected with said lever and adapted to move same in reverse directions; electric conducting means for alternatively energizing the solenoid coil of either electromagnet; and means responsive to the outside air temperature for controlling the flow of current in said electric conducting means.

7. An instrument for controlling the operation of air conditioning equipment comprising, in combination, a thermostatic element responsive to variations in the temperature of air in an enclosure; a hygrostatic element responsive to variations of relative humidity of air in said enclosure, an adjustable element, common to both the thermostatic and hygrostatic elements and coacting synchronously with each; a ratchet, adapted to move in reverse directions and operatively connected with said adjustable element; two contro-positioned pawls, adapted to engage the teeth of said ratchet; a reversibly acting lever, adapted to be fulcrumed at either of two points and pivotally supporting said pawls; two electromagnets, oppositely connected with said lever and adapted to move same in reverse directions; electric conducting means for alternatively energizing the solenoid coil of either electromagnet; and switch means controlling the flow of current in said electric conducting means, said switch means being operative to energize one of said electromagnets upon movement in one direction and operative to energize the other of said electromagnets upon movement in the opposite direction.

8. In combination with an enclosure to be air conditioned; air conditioning equipment comprising a compressing unit, a condensing unit and an evaporating unit in refrigerant flow relationship; a controlling unit comprising, in combination, hygrostatic means responsive to variations of relative humidity for varying the amount of moisture removed from the air by the evaporating unit;

thermostatic means responsive to variations of temperature for progressively varying the capacity of said compressing unit; and an adjustable element, common to both the thermostatic and the hygrostatic elements and coacting synchronously with each.

ALBERT E. BEALS. 

